ar71xx: rework changes from r35840

Signed-off-by: Luka Perkov <luka@openwrt.org>
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt@35865 3c298f89-4303-0410-b956-a3cf2f4a3e73
[package] uboot-env: wzr-600dhp uses wzr-hp-ag300h name

git-svn-id: svn://svn.openwrt.org/openwrt@35866 3c298f89-4303-0410-b956-a3cf2f4a3e73